<form class="login" action="/user/login" method="POST" >
    <label for="username" >
        用户名
    </label>
    <input id="username" name="username" />
    <label for="pwd">
        密码
    </label>
    <input id="pwd" type="password" name="pwd" />
    <p class="err" ><%= msg %></p>
    <input type="submit" value="登录" />
</form>